KMAC (Keccak Message Authentication Code) is a cryptographic function based on the Keccak sponge construction, which is also the basis for SHA-3. KMAC is designed to provide message authentication and integrity verification, ensuring that data has not been altered and originates from a legitimate source. Unlike traditional HMAC, KMAC offers greater flexibility in parameter selection, such as output length and customization strings, making it suitable for a wide range of applications. It is standardized by NIST and can be used for both message authentication codes (MACs) and key derivation functions (KDFs). KMAC is resistant to known cryptographic attacks and is recommended for modern security systems.